187 research outputs found

    Implementation of CPRI Protocol in Digital Repeater on FPGA

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    为了开发数字直放站连接系统,介绍CPrI协议规范和帧结构,讨论其硬件上的实现方案,给出基于SCAn25100的fPgA电路模块设计,采用VErIlOg语言设计开发功能模块。该方案具有便于功能扩展、成本低、使用灵活等特点,通过实际测试表明,此方案可进行可靠的数据传输,性能稳定,从而实现了数字直放站和基站之间更有效的互通,扩大了基站的覆盖范围。To develop the connection of digital repeaters,CPRI protocol specification and frame structure are introduced.Its implementation on hardware is discussed.The detail module design of FPGA circuit and program based on SCAN25100 are elaborated.The design is easy to expand and low cost.The experimental analysis shows that the solution could accomplish the data transmission,and the interconnection between base station and digital repeater are implemented,the network′s coverage is enhanced.福建省重大专项基金资助项目(2007HZ003

    Distribution pattern of PAHs in Jiulong River Estuary by both measurement and simulation

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    于2011年12月(冬季)在厦门九龙江河口及西港采集9个表层海水水样,采用固相萃取—气质联用方法(SPE-GC-MS)分析其中16种多环芳烃含量。研究结果表明,总溶解态态∑PAH含量为157.9~858.0 ng/L。在河口区,随着盐度升高,PAHs含量逐渐降低。基于比值法分析,表明厦门九龙江及西港海域海水中的PAHs来源存在多种途径,呈现混合来源的态势。利用LEVEL III逸度模型研究菲,芘和苯并(a)芘在各介质间的分布以及水——气界面的交换通量。模拟结果与本文实测和文献中的实测值相吻合。在16℃时,三种多环芳烃的大气沉降通量分别为17.38,7.86和8.38μg/day/m2。其中菲在大气沉降中占主导地位,约三分之二。三种多环芳烃的大气沉降通量均随温度升高而减少。当温度高于32℃时,苯并(a)芘开始从水体释放。The concentration of 16 polycyclic aromatic hydrocarbons( PAHs) of nine water samples,collected in the Jiulong River Estuary in December,2011,were analyzed using the SPE-GC-MS method. The results showed that the concentration range of total dissolved PAHs( ΣPAHs) was from 157. 9 to 858. 0 ng / L. The horizontal distribution illustrated that the concentration of ΣPAHs decreased as salinity increased. Based on ratio analysis,PAHs have complicated sources. A Level III fugacity model was developed to simulate the multimedia fate of PAHs and to study the air-water exchange fluxes of three PAHs( phenanthrene,pyrene,benzo[a]pyrene) in the Jiulong River Estuary. The calculated concentration of PAHs was similar to that measured in this study or reported in earlier literature. At 16℃,the net atmosphere deposition fluxes of these PAHs were 17. 38,7. 86 and 8. 38 μg / day / m2. Phenanthrene was predominant in the atmospheric deposition. The net atmospheric deposition fluxes of these PAHs all decreased with tem-perature. When the temperature was above 32. 0℃,benzo[a]pyrene was released from the water into the air.国家自然科学基金(40776044);; 福建省自然科学基金(2012J05078);; 福建省杰出青年科学基金(2014J06014);; 中央高校基本科研专项(20720140507

    Application of Micro multimedia Demonstrating System in Experiments of Botanical Biology

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    介绍显微多媒体教学系统的组成、功能及其在植物生物学实验教学中的应用。该系统的应用 ,开拓了学生由感性认识上升到理性认识的新途径 ,极大地增强了实验教学过程的生动性和灵活性 ,明显地提高了教学效率和质量。The micro multimedia demonstrating system is composed of biological microscope, colour video camera, computer and LCD projector. This system, which combines microtechnique with the advanced multimedia technique, makes the teaching of experiments of botanical biology not only very audio visual and lively but also more rapid and effective.国家基础科学生物人才基地专

    Developing On-site,Quick Screening Platform for Artificial Pigments in Food Using Surface-enhanced Raman Spectroscopy

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    已有研究表明食品加工过程中添加的人工合成色素不仅不能提供营养物质,而且可能是导致小儿多动症的来源之一,影响儿童智力发育.基于表面增强拉曼光谱(SERS)原理和便携式拉曼光谱仪,提出了一种非定向的现场快速筛查方法.该方法只需对疑似含有人工合成色素的固体或液体状食品样品进行简单前处理,即可进行SERS检测.样品前处理和检测的总时长不超过15 min,检出质量浓度在1 mg/L水平,可有效满足政府职能部门的现场执法需求.除具有快速、方便、灵敏度高等特点之外,该检测方法的最大优势在于实现了未知样品的现场非定向测试:在同一种前处理过程和检测方法下,可对食品中常添加的亮蓝、胭脂红、日落黄、柠檬黄、苋菜红和诱惑红6种人工合成色素进行快速鉴定和半定量分析.As widely used additives in food processing,artificial pigments have no any nutrition but are potential sources of hyper-activity and affect the intellectual development of children.On the basis of surface-enhanced Raman spectroscopy( SERS) and portable Raman instrument,we developed a non-targeting,on-site and quick screening platform for artificial pigments in food matrix. SERS measurement could be carried out after the food matrix( either in solid or liquid states) being simply pretreated for 15 min.The detectable concentration is as low as 1 mg / L,a level meeting the demand of the on-site enforcement by the government.Besides the advantages of quick,easy-on-going,and high sensitivity,the most distinguished point of SERS is the non-targeting qualitative on-site detection for the typical pigment additives,including brilliant blue,carmine,sunset yellow,lemon yellow,amaranth and allura red,et al.,while both the pretreatment procedure and the SERS detection remain the same.国家自然科学基金(21473140);; 福建省高校产学合作项目(2016Y4012);; 中央高校基本科研业务费专项(2072016011

    Influence of Particle Damper Configurations on the Dynamic Characteristic for Gear Transmission System

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    齿轮传动正朝着高速、重载和高精度方向发展,对其动态性能要求越来越高。颗粒阻尼通过颗粒间、颗粒与阻尼器壁间的非弹性碰撞和摩擦作用耗能,具有减振效果; 显著、耐高温、各向同性、对原结构改动小等优点。利用有限元法对齿轮进行了有预应力的模态分析,通过齿轮系统动力学分析,研究单双齿啮合激励对齿轮传动的; 影响;同时建立齿轮传动离心场中颗粒系统耗能模型,将离散元法计算颗粒系统耗能和试验测试对比,分析阻尼器配置对齿轮传动系统动特性的影响。结果显示,阻; 尼器配置方案是影响齿轮传动系统动特性的一个重要因素,在阻尼孔中填充一定数量的颗粒,当阻尼器总体积相同且齿轮结构静刚度相差不大时,阻尼器个数越多颗; 粒系统能耗越大;当阻尼孔直径相同时,阻尼孔个数越多颗粒系统总能耗越小;当阻尼孔个数相同时,阻尼孔直径越大颗粒系统能耗越小。通过试验和仿真对比验证; 了模型的正确性,为颗粒阻尼在离心场中的应用提供重要的理论依据。The gear transmission is advancing towards high speed, heavy load and; high precision. The requirements for the dynamic performance of gear; system are urgently proposed. The particle damping dissipates mechanical; system energy through inelastic collisions and friction between; particles. It is an effective and simple measure for vibration; reduction. It has many advantages, such as isotropy, high temperature; resistance and less modification to the original structure. This paper; has conducted the prestressed modal analysis of gear system by the; finite element method. Based on the dynamics analysis of gear system,; the effect of single tooth and double teeth meshing incentive on gear; transmission has been analyzed. The energy dissipation model of particle; damping for gear transmission in centrifugal field has been established.; By contrasting theoretical analysis and the test, the effect of damper; configuration on dynamic characteristic of gear transmission system is; analyzed. The results show that damper configuration is an important; factor of the dynamic characteristic for gear transmission system.; Filling a certain number of particles, when the gears static stiffness; are similar and the total dampers volume are equal, the more damping; hole, the greater the total energy loss. When the damping holes diameter; are the same, the more number of damping hole, the smaller the total; energy loss. When the damping hole number is the same, the bigger the; diameter, the less the total energy loss. Experimental results are; consistency with the theoretical analysis. These results can provide; guidelines for the application of particle damping in centrifugal field.国家自然科学基金; 福建省重点科技专项; 中央高校基本科研业务费专项资金; 福建省高端装备制造协同创新中心资助项

    Principle and development of programmable RF transceiver CC1100

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    介绍了Chipcon公司推出的一款具有极低功耗的可编程RF收发器CC1100的功能特点,给出了CC1100的应用电路设计及芯片配置方法,最后讨论了RF开发中常见的问题及解决方案。The characteristics of the ultra low power RF transceiver CC1100 produced by Chipcon Company are introduced.The application circuit design and configuration are given.The general questions of RF research and its solutions are also discussed

    基于粒子群优化的无线传感器网络节点定位改进

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    针对无线传感器网络低成本、低功耗的要求, 提出了一种DV-Hop改进算法, 利用节点间的估计距离和锚节点的位置, 在DV-Hop算法的第三阶段使用粒子群优化的方法校正DV-Hop得到的估算位置。该算法不需要任何额外硬件设备和不增加通信量。仿真表明, 改进的算法可以使DV-Hop的平均定位误差下降30%, 并有效降低了成本

    基于小波变换的大尺度岩体结构微震监测信号去噪方法研究

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    为将小波去噪方法应用于大尺度岩体结构微震监测信号的去噪研究,首先在MAT-LAB环境下进行仿真,验证了使用Symlet6小波进行小波去噪的可行性;利用4种自适应阈值规则对含噪信号进行去噪对比,结果表明4种阈值去噪后的信号在均方差较小的情况下都极大地提高了信号的信噪比,有效地去除了噪声,对不同的含噪信号,无偏似然原则阈值去噪后的信噪比最高,同时均方差也最小,在去噪时显得更为有效;以柿竹园全数字多通道微震监测系统为背景,将MATLAB仿真结论应用于现场微震信号的去噪研究,结果表明小波阈值去噪特别适合大尺度岩体微震信号这一类非稳定信号的去噪分析,既可以对低信噪比的微震信号提取出有效信号,也可以对频率覆盖范围广的微震信号在各尺度上提取并重构出有效信号,实现了对微震真实信号和噪声信号的有效分离

    The Development of a New Type of Medical Rehabilitation Brace for Lower Limbs

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    本文阐述了一种新型医用下肢康复支具的研制过程。该装置主要由承重装置、负重装置、负重调节装置以及压力检测装置等结构组成,具有调节、设定以及控制负重载荷等功能,可使行内固定术后的下肢骨折患者早期进行负重、行走功能锻炼,促进其骨折愈合及肢体功能康复,减少术后并发症,具有一定的实用价值。The paper expounded the development of a new type of medical rehabilitation brace for lower limbs. The device was mainly composed of different structures including the hip weight-bearing device, the foot weight-bearing device, the weight-bearing adjustment device and the pressure detection device. The brace was designed to allow patients to carry out weight-bearing exercises and walking exercises in early postoperative period after receiving internal fixation of lower limb fracture. It could also promote fracture healing and functional recovery of lower limbs and reduce postoperative complications, which is of certain clinical value

    用双爆轰驱动的激波管技术

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    本文通过对前向双爆轰驱动和前向单爆轰驱动激波管实验比较证实:在双氢氧爆轰驱动激波管中,辅驱动段的初始压力只需大于主驱动段初始压力的几倍,且辅驱动段的长度比主驱动段短许多,便可在被驱动段获得比单氢氧爆轰驱动较低的入射激波衰减率,且P5区获得更长的驱动时间
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